From Dog To A Police Dog

The police departments can procure K9s in two ways. They can buy a “green dog,” which is basically a 7 to 14-month-old that has been trained with basic obedience. The green dog is sent to a 4-12 week training with the officer it has been assigned to. And the other option is to buy a dog which has already gone through this training, and then the dog is assigned to the officer. But how do they decide which officer should get the K9?